D. S. Leonard
A5028115821- Dark Matter and Cosmic Phenomena
- Particle physics theoretical and experimental studies
- Atomic and Subatomic Physics Research
- Neutrino Physics Research
- Particle Detector Development and Performance
- Nuclear physics research studies
- Radiation Detection and Scintillator Technologies
- Astrophysics and Cosmic Phenomena
- Quantum, superfluid, helium dynamics
- Quantum Chromodynamics and Particle Interactions
- Nuclear Physics and Applications
- Atomic and Molecular Physics
- Cosmology and Gravitation Theories
- Superconducting Materials and Applications
- Advanced NMR Techniques and Applications
- Spacecraft and Cryogenic Technologies
- Scientific Research and Discoveries
- High-Energy Particle Collisions Research
- Crystallography and Radiation Phenomena
- Nuclear reactor physics and engineering
- Advanced Chemical Physics Studies
- Cancer, Hypoxia, and Metabolism
- Enzyme Structure and Function
- Methane Hydrates and Related Phenomena
- Terahertz technology and applications
Institute for Basic Science
2015-2025
The University of Tokyo
2024
Universidad Europea
2024
University of Victoria
2024
Korea University of Science and Technology
2021
Korea Research Institute of Standards and Science
2021
Kavli Institute for Particle Astrophysics and Cosmology
2017-2020
SLAC National Accelerator Laboratory
2017-2020
Stanford University
2017-2020
Seoul National University
2015
The Large Underground Xenon (LUX) experiment is a dual-phase xenon time-projection chamber operating at the Sanford Research Facility (Lead, South Dakota). LUX cryostat was filled for first time in underground laboratory February 2013. We report results of WIMP search data set, taken during period from April to August 2013, presenting analysis 85.3 live days with fiducial volume 118 kg. A profile-likelihood technique shows our be consistent background-only hypothesis, allowing 90% confidence...
We present new constraints on the dark matter-induced annual modulation signal using 1.7 years, of COSINE-100 data with a total exposure 97.7 kg$\cdot$years. The experiment, consisting 106 kg NaI(Tl) target material, is designed to carry out model-independent test DAMA/LIBRA's claim WIMP discovery by searching for same target. crystal show 2.7 cpd/kg/keV background rate average in 2--6 keV energy region interest. Using $\chi$-squared minimization method we observe best fit values amplitude...
COSINE is a dark matter search experiment based on an array of low background NaI(Tl) crystals located at the Yangyang underground laboratory. The assembly COSINE-100 was completed in summer 2016 and detector currently collecting physics quality data aimed reproducing DAMA/LIBRA that reported annual modulation signal. Stable operation has been achieved will continue for least two years. Here, we describe design COSINE-100, including shielding arrangement, configuration crystal detection...
Abstract AMoRE-II aims to search for neutrinoless double beta decay ( $$0\nu \beta $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>0</mml:mn> <mml:mi>ν</mml:mi> <mml:mi>β</mml:mi> </mml:mrow> </mml:math> ) with an array of 423 $$\hbox {Li}_2^{100}\hbox {MoO}_4$$ <mml:msubsup> <mml:mtext>Li</mml:mtext> <mml:mn>2</mml:mn> <mml:mn>100</mml:mn> </mml:msubsup> <mml:msub> <mml:mtext>MoO</mml:mtext> <mml:mn>4</mml:mn> </mml:msub> crystals operating in the cryogenic...
AMoRE searches for the neutrinoless double beta decay using 100 kg of enriched Mo100. Scintillating molybdate crystals coupled with a metallic magnetic calorimeter operate at milli-Kelvin temperatures to measure energy electrons emitted in decay. AMoRE-I is demonstrator full-scale AMoRE, operated Yangyang Underground Laboratory over two years. The exposure was 8.02 year (or 3.89 kgMo100 year), and total background rate near Q value 0.025±0.002 counts/keV/kg/year. We observed no indication...
The Korea Invisible Mass Search (KIMS) collaboration has developed low-background NaI(Tl) crystals that are suitable for the direct detection of WIMP dark matter. Building on experience accumulated during KIMS-CsI programs, KIMS-NaI experiment will consist a 200 kg crystal array surrounded by layers shielding structures and be operated at Yangyang underground laboratory. goal is to provide an unambiguous test DAMA/LIBRA annual modulation signature. Measurements six prototype show progress in...
The COSINE-100 dark matter search experiment has started taking physics data with the goal of performing an independent measurement annual modulation signal observed by DAMA/LIBRA. A muon detector was constructed using plastic scintillator panels in outermost layer shield surrounding detector. It detects cosmic ray muons order to understand impact on analysis. Assembly and initial performance tests each module have been performed at a ground laboratory. installation Yangyang Underground...
The AMoRE-II experiment will search for the 0 νββ decay of 100 Mo nuclei using molybdate crystal scintillators, operating at milli-Kelvin (mK) temperatures, with a total 80 kg Mo. background goal is 10 –4 counts/keV/kg/year in region interest around Q-value 3,034 keV. To achieve this level, rate signals arising from emissions produced by decays radioactive impurities detector and shielding materials must be strictly controlled. do this, concentrations such are measured controlled through...
Abstract The AMoRE collaboration searches for neutrinoless double beta decay of $$^{100}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mmultiscripts> <mml:mrow/> <mml:mn>100</mml:mn> </mml:mmultiscripts> </mml:math> Mo using molybdate scintillating crystals via low temperature thermal calorimetric detection. early phases the experiment, AMoRE-pilot and AMoRE-I, have demonstrated competitive discovery potential. Presently, AMoRE-II featuring a large detector array with...
We present new accurate measurements of the differential cross section $\ensuremath{\sigma}(\ensuremath{\theta})$ and proton analyzing power ${A}_{y}$ for proton-$^{3}\mathrm{He}$ elastic scattering at various energies. A supersonic gas-jet target has been employed to obtain these low-energy cross-section measurements. The distributions have measured ${E}_{p}=0.99$, 1.59, 2.24, 3.11, 4.02 MeV. Full angular ${E}_{p}=1.60$, 2.25, 3.13, 4.05 This set high-precision data is compared four-body...
Recent Wilkinson Microwave Anisotropy Probe (WMAP) measurements have determined the baryon density of Universe ${\ensuremath{\Omega}}_{b}$ with a precision about 4%. With tightly constrained, comparisons Big Bang nucleosynthesis (BBN) abundance predictions to primordial observations can be made and used test BBN models and/or further constrain abundances isotopes weak observational limits. To push limits improve constraints on models, uncertainties in key nuclear reaction rates must...
The LUX-ZEPLIN (LZ) experiment will enable a neutrinoless double $\ensuremath{\beta}$ decay search in parallel to the main science goal of discovering dark matter particle interactions. We report expected LZ sensitivity $^{136}\mathrm{Xe}$ decay, taking advantage significant ($>600$ kg) mass contained within active volume without isotopic enrichment. After 1000 live-days, median exclusion half-life is projected be $1.06\ifmmode\times\else\texttimes\fi{}{10}^{26}$ years (90% confidence...
LUX-ZEPLIN is a dark matter detector expected to obtain world-leading sensitivity weakly-interacting massive particles interacting via nuclear recoils with $\ensuremath{\sim}7$-tonne xenon target mass. This paper presents projections several low-energy signals of the complementary electron recoil signal type: 1) an effective neutrino magnetic moment, and 2) millicharge, both for $pp$-chain solar neutrinos, 3) axion flux generated by Sun, 4) axionlike forming Galactic matter, 5) hidden...
The Large Underground Xenon (LUX) experiment is a liquid xenon time projection chamber designed for extremely low levels of radioactive background in its fiducial volume. overall mass 300 kg, with 100 kg mass. LUX currently under construction, and integration the full detector will begin Fall 2009 at Sanford Science Engineering Laboratory South Dakota. sensitivity to WIMP-nucleon spin-independent scattering cross-section be 7 × 10-46 cm2 GeV after days low-background operation.
We present a search for low-mass ($\leq 20 GeV/c^{2}$) weakly interacting massive particles(WIMPs), strong candidates of dark matter particles,using the low-background CsI(Tl) detector array Korea Invisible Mass Search (KIMS) experiment. With total data exposure 24,324.3kg$\cdot$days,we WIMP interaction signals produced by nuclei recoiling from WIMP-nuclear elastic scattering with visible energies between 2 and 4keV. The observed energy distribution candidate events is consistent null...
We have successfully built and operated a source deployment system for the KamLAND detector. This was used to position radioactive sources throughout delicate 1-kton liquid scintillator volume, while meeting stringent material cleanliness, compatibility, safety requirements. The calibration data obtained with this device were fully characterize detector energy reconstruction biases. As result, uncertainty in size of fiducial volume reduced by factor two. Prior system, largest systematic...